1. Field of the Invention
The present invention relates generally to vehicle security systems, having the ability to disable the normal operation of the vehicle and communicate an alarm state in response to an intrusion or a remote signal.
2. Discussion of Prior Art
Vehicle security systems have evolved over time. One of the more significant contributions of these systems is the remote access to the vehicle and the ability to disable one or more of the normal operating functions, such as the ability to start the vehicle. In an armed state, the prior art systems were designed to prevent the vehicles from starting when an unauthorized person engaged the ignition switch to its start position. To achieve this functionality, the prior art security systems placed a security controller, operable in communication with a remote control transmitter. The controller controlled the operation of a cutoff relay placed in between the ignition switch and the starter solenoid. The current path to the starter solenoid, normally completed by placing the ignition switch to the start position, was interrupted by the cutoff relay when the controller was in its armed state. Thus, the vehicle could not be started. Such cutoff relays followed two distinct functional principles.
One employed a normally-open cutoff relay and the other a normally-closed cutoff relay. In a system employing a normally-open relay, if the relay fails in its biased, normally-open position, the vehicle would not start even if the controller is placed in its disarmed state. This leads to much frustration, safety and security concerns for the vehicle and its operator. It further leads to significant costs. The operator is usually frustrated when his/her vehicle is disabled by a relatively inexpensive, failed relay, especially when this relay is an aftermarket product.
The second principle employed a biased, normally-closed relay. If this relay fails, it fails in its biased, normally closed position. Accordingly the current path from the ignition switch to the starter solenoid is functional and transparent to the user. On the upside, the user is not frustrated by a disabled vehicle. On the downside the vehicle is less secure.
With time, vehicle manufacturers (“OEMs”) began to integrate the security and convenience functionality into their vehicles. Aftermarket providers, however, have continued to stay ahead, innovate and offer enticing value-add security and user convenience features not adopted by the OEMs. Accordingly, with the complexity of vehicles' electrical systems, and the entry of OEM security features, aftermarket suppliers are advantaged by coexisting with the OEM functionality and continuing to integrate innovative enhancements in conjunction with the OEM systems.